Heart substructural dosimetric parameters and risk of cardiac events after definitive chemoradiotherapy for stage III non-small cell lung cancer

Abstract

Introduction: We evaluated the incidence of cardiac events after chemoradiotherapy in patients with stage III non-small cell lung cancer (NSCLC) based on baseline cardiovascular risk and the heart substructures' radiation dose.

Methods: From 2008 to 2018, the cardiac events of 258 patients with stage III NSCLC who received definitive chemoradiotherapy were reviewed. The 10-year cardiovascular risk was calculated using the Atherosclerotic Cardiovascular Disease (ASCVD) scoring system. Dose-volume histograms were estimated for each cardiac chamber. A multivariate competing-risk regression analysis was conducted to assess each cardiac event's subhazard function (SHR).

Results: The median follow-up was 27.5 months overall and 38.9 months for survivors. Among the 179 deaths, none was definitely related to cardiac conditions. Altogether, 32 cardiovascular events affected 27 patients (10.5%) after chemoradiotherapy. Ten were major cardiac adverse events, including heart failure (N = 6) and acute coronary syndrome (ACS, N = 4). Most cardiovascular events were related to well-known risk factors. However, the volume percentage of the left ventricle (LV) receiving 60 Gy (LV V60) > 0 was significantly associated with ACS (SHR = 9.49, 95% CI = 1.28-70.53, P = 0.028). In patients with high cardiovascular risk (ASCVD score > 7.5%), LV V60 > 0% remained a negative ACS prognostic factor (P = 0.003). Meanwhile, in patients with low cardiovascular risk, the LV radiation dose was not associated with ACS events (P = 0.242).

Conclusions: A high LV radiation dose could increase ACS events in patients with stage III NSCLC and high cardiovascular risk. Pre-treatment cardiac risk evaluation and individualized surveillance may help prevent cardiac events after chemoradiotherapy.

Keywords: Cardiac event; Chemoradiotherapy; Dosimetry; Heart substructure; Lung cancer.